1. Field of the Invention
The present invention relates generally to electrosurgical devices for incising and cauterizing soft tissue and other anatomical structures. The present invention relates more particularly to electrosurgical devices which aspirate smoke produced by incision and cauterization.
2. Discussion of the Prior Art
Electrosurgical devices have been developed to substitute "cold" scalpels for incising soft tissue and other anatomical structures during surgical procedures. A typical electrosurgical device provides a blade or needle which represents one electrode in a circuit completed by a grounding electrode attached to an extremity of the patient. Electric power is applied to the electrode blade by appropriate means. Upon application of the electrically charged blade to the anatomical surface, a voltage gradient is created, thereby inducing current flow and related heat generation at the point of contact. A sufficiently large voltage gradient generates sufficient heat to incise or cut the tissue. Electrosurgical devices represent an improvement in incising instruments because the heat generated by an electrosurgical device can also cauterize the anatomical structure after incision to reduce or stop the associated bleeding.
Some electrosurgical devices have control circuitry for selectively generating a relatively high voltage for incision and relatively low voltage for cauterization only. Selection between the two levels can be made by manipulation of switch controls, such as buttons on a handle of the electrosurgical device.
Although electrosurgical devices provide many advantages, a significant drawback of their use is the smoke produced during incising and cauterization. Incision and cauterization using an electrosurgical device can generate substantial amounts of smoke. The smoke can obscure or impair the vision of the operating surgeon. Additionally, the smoke can be an irritant to the surgeon's eyes, thereby interfering with the progress of surgical procedures.
Smoke generation can be particularly troublesome in closed spaces, especially during intrathoracic, flap development and oropharyngeal procedures. In such operations, an extended blade is sometimes used to incise surfaces several inches inside a closed space cavity. The smoke generated at the point of incision can accumulate in the cavity. This accumulated smoke can severely obscure the surgeon's view of the operative site.
The smoke can also perpetuate the smell of burning flesh. This smell can be distracting to the operating surgeons, attending nurses and technicians as well as the patient, if conscious during the operating procedure.
Of particular significance and concern, it has been discovered that the smoke produced by electrosurgical incisions and cauterizations can contain and transport viable virile DNA. The viruses transmitted by the smoke present a significant health hazard to the operating surgeon and others present in the operating room.
Systems have been developed for aspirating smoke produced by electrosurgical procedures. In a typical technique, the smoke is aspirated by a conventional hospital suction tube held near the site of the electrosurgical procedure by a medical technician. This method inefficiently occupies the attention of a technician. The placement of the often bulky suction tube in the operative field can also obstruct the operating surgeon's view.
Other systems have been developed to overcome these disadvantages. In Plastic and Reconstructive Surgery, (Volume 85, No. 5, November, 1989, Page 855), Young et al. disclose smoke aspirating apparatus constructed piecemeal from various medical supplies available in an operating room. The apparatus includes a conventional catheter attached to the side of an electrocautery pencil so that the catheter inlet is positioned near the "cutting" end of the electrocautery blade. The catheter is secured to the electrocautery pencil by adhesive tape and is connected at its outlet end to standard hospital suction tubing.
The on-site construction of this apparatus prior to operation is inconvenient and can expose the assembler to puncture or cuts from the electrocautery needle or blade. Such wounds present a substantial health hazard during the subsequent operation.
Additionally, the adhesive tape used to secure the catheter to the electrocautery pencil can become saturated with blood and other fluids during the operating procedure and thereby unravel or disintegrate. Consequently, the catheter can become separated from the electrocautery pencil during the surgery. In addition to being inconvenient, the separating catheter can possibly injure the patient.
In closed space procedures in which the catheter is taped to an extended blade, the separation of tape inside the cavity presents a significant danger. Pieces of tape or adhesive can separate and become lost in the cavity. If these foreign bodies are not discovered and removed, post-operative infections can occur.
The taping of the catheter to the blade also interferes with the blade changing that is sometimes required during surgery. Further, the taped catheter can prevent cleaning of char which collects on the blade during surgery.
In ENTechnology, (August, 1990, Page 562), Johnson et al. have also disclosed apparatus for aspirating smoke during electrosurgical procedures. The apparatus is constructed by threading a needle tip of an electrosurgical pencil blade into the suction end of a catheter so that a few millimeters of the needle remain exposed to perform incision. The shrouding of the needle with the catheter provides insulation of the needle against inadvertent burning of tissue adjacent to the desired site.
In this construction, the catheter is again attached to the electrosurgical pencil by adhesive tape. Although the threading of the electrosurgical needle tip through the catheter end reduces the likelihood of separation at the tip, separation along the length of the electrosurgical device can nevertheless occur if the adhesive tape unravels or disintegrates.
The insertion of the electrosurgical needle tip through the suction end of the catheter increases the risk of puncture or cut to the assembling surgeon during construction. Such wounds can present a health risk during surgical procedures. Also, the shrouding catheter can interfere with blade changing during surgery, further increasing the risk of a puncture or cut.